Humans, on Earth, are always using the Global Positioning System (GPS) to navigate our way through new places or to find our way when we are lost. So, why should we not extend that service to space, where the possibility of getting lost is high and can take a fateful turn?
NASA wants to do just that and hence they are working towards a GPS that could be used to pilot in and around the lunar orbit during the Artemis mission. On previous missions, navigation was provided by NASA’s communication network. By using this method, it will ease the load on the NASA network and make it possible to send other more valuable data.
A GPS system is made up of three parts: satellites, ground stations, and receivers. The ground stations monitor satellites, and a receiver is constantly listening for a signal from those satellites. The receiver calculates its distance from four or more satellites to pinpoint an exact location. Scientists at NASA are developing a special receiver that will be able to pick up location signals provided by the 23-24 GPS satellites that are operated by the military.
The spacecraft that is fitted with this GPS receiver will be paired with precise mapping data that will enable astronauts to track their locations in space or on the Moon’s surface.
The GPS receiver is based on the Goddard-developed Navigator GPS, which engineers began developing in the early 2000s specifically for NASA’s Magnetospheric Multiscale mission (MMS) mission, which was NASA’s unpiloted space mission to study the Earth’s magnetosphere, and used four identical spacecraft flying in a triangular pyramid formation.
“We’re using infrastructure that was built for surface navigation on Earth for applications beyond Earth,” said Jason Mitchell, chief technologist for Goddard’s Mission Engineering and Systems Analysis Division, in a press release. “Its use for higher-altitude navigation has now been firmly established with the success of missions like Magnetospheric Multiscale mission and the Geostationary Operational Environmental Satellites (GOES). In fact, with MMS, we’re already nearly halfway to the Moon.”
To make this GPS a reality, the old MMS’s GPS will need some upgrades, like a high-gain antenna, an enhanced clock, and updated electronics.
The team’s current lunar GPS receiver concept is based on NavCube, a new capability developed from the merger of MMS’s Navigator GPS and SpaceCube, a reconfigurable, very fast flight computer platform.